It has been found that the stop at the upper end of the drop pipe slide member shown in the positive seal pitless well adapter of Wellstein's U.S. Pat. No. 3,812,910 issued May 28, 1974 does not relieve any of the outward strain on the parallel flanges of the track on the hanger member into which it slides, particularly if this hanger member is made of plastic instead of metal.
Furthermore it has been found that relative increases in pressure in the duct through the hanger member and its nipple can cause leakage around the nipple portion of the hanger member between the gasket and the outside wall of the nipple, which leakage will prevent this adapter passing some of the State codes requiring such gaskets to be pressurized.
Accordingly, it is a purpose of this invention to improve the adapter shown in this Wellstein U.S. Pat. No. 3,812,910, and to overcome its above mentioned inadequacies.